In this thesis, the impacts of US subprime mortgages event and its regulatory forbearance policy on Taiwan’s financial system are examined. This thesis first investigates the causes and impacts of financial turmoil due to subprime mortgage event. Second, we explore the impacts of US subprime mortgages event on global financial system. This thesis will examine not only the impacts of the event on the infrastructure of global financial markets, but also the impacts of the event on risk management of global financial institutions. Finally, we explore the impacts of US subprime mortgages event on Taiwan’s regulatory policy. Due to the impacts, we discuss how to enhance Taiwan’s ratings agencies and the infrastructure of Taiwan’s financial markets. Also, we sum up how to strengthen risk management practices for Taiwan’s financial institutions. Besides, we also investigate how to enhance prudential regulatory policies for Taiwan’s financial system.